1. Field of Invention
The present invention relates to a hand-held power screwdriver with a low-noise torque clutch.
2. Description of the Prior Art
In the hand-held power screwdrivers used for screwing in of screws, in order to prevent overrotation of a screw, force flow from the drive motor to the screw-driving tool is interrupted upon the torque reaching a predetermined threshold. A conventional torque clutch has two rachet clutches preloaded against each other. The ratchet members have respective, circumferentially arranged, oblique cams. The drawback of a conventional ratchet clutch is a disturbing loud grating which in addition to noise, which leads to a significant wear of the ratchet clutch.
European Patent EP990488B1 discloses a hand-held power screwdriver with a low-noise torque clutch which is formed as a combination of a ratchet clutches. To this end, oblique cams are formed on opposite sides of an axially displaceable ratchet member and are associated with two axially spaced ratchet clutches. The combination torque clutch is unnecessarily very complex and, with two ratchet clutches, the wear of the power screwdriver is unnecessarily high.
Accordingly, an object of the present invention is to provide a hand-held power screwdriver with a low-noise torque clutch having a low wear.